Thermoplastic materials have transformed consumer and industrial products, replacing metal, glass, and wood, because such thermoplastic materials do not rust, shatter, or rot, respectively.
Poly(vinyl halide), especially poly(vinyl chloride), has become a common building material for siding, windows, decking, etc. The goal of using poly(vinyl halide) products to create the appearance of the use of original materials.
Simulated appearance by plastic of a metal, glass, or wood item greatly depends on how it is made. As between extrusion and molding, for example, extrusion is a continuous operation through a die that configures the profile dimensions of the thermoplastic item but has no practical ability to provide simulated appearance on the surfaces of the item not on the edges of the profile.
It is possible to “stamp” a simulated appearance on such surfaces, but the simulation precision suffers from that batch-wise effort to make an extruded product appear molded.
Molded articles, therefore, have a much better chance of serving to simulate the metal, glass, or wood article the thermoplastic molded article is designed to replace. However, those skilled in the art of injection molding, for example, know how difficult it is to reconcile the rheology of the thermoplastic being molded with the processing parameters of the molding equipment.